PSI - Issue 42

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Ricardo Pires et al. / Procedia Structural Integrity 42 (2022) 639–646 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 6. Stress values at critical locations on the hybrid tube and the EGR inner fin for the 445M2 ferritic stainless steel. Fig. 7. First natural frequency and mass evolution with the growth of the inner fin.

4. Conclusions This section presents the relevant conclusions drawn from this work, namely:

• The gas temperature drop proves to be more efficient with the increasing length of inner fins; • However, thermomechanical analysis indicates that a shorter distance between the fins and the baffle results in higher thermal stresses induced at the entry of the fins; • Therefore, shorter fins prove to have a longer duration as a result of lower thermal stresses induced; • The use of a 445M2 ferritic stainless steel resulted in an improvement of the heat transfer process and lower stresses of the overall assembly in comparison to the annealed stainless steel; • The phenomena of resonance will not occur in the EGR system; • For a period of 10 years, when three thermal cycles/day is considered, the reference length of 120 mm for the fins should be adopted. Acknowledgements The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT.IP) for its financial support through the grant UIDB/00667/2020 (UNIDEMI). References Abd-Elhady, M. S., Malayeri, M. R., Müller-Steinhagen, H. (2011). Fouling problems in exhaust gas recirculation coolers in the automotive industry, Heat Transf. Eng., vol. 32, no. 3 – 4, pp. 248 – 257. Austral Wright Metals, The new marine grade stainless steel, 445M2-bro.pdf (australwright.com.au) (accessed on 17 August 2022) Grande, J., Carrera, J.A., Dieguez, M., (2017). Development of High-Performance Plug&Cool EGR Coolers for CV Applications, SAE Technical Paper, Mar. 2017, 2017-01-1089, https://doi.org/10.4271/2017-01-1089 Infante, V., Branco, C.M., Martins, R. (2003). A Fracture Mechanics Analysis on the Fatigue Behaviour of cruciform joints of Duplex Stainless Steel, Fatigue Fract Engng Mater Struct, 26, pp. 791-810. Ladommatos, N., Abdelhalim, S., Zhao, H., and Hu, Z., (1996a). The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Diesel Engine Emissions - Part 1: Effect of Reducing Inlet Charge Oxygen," SAE Technical Paper 961165, https://doi.org/10.4271/961165 Ladommatos, N., Abdelhalim, S., Zhao, H., and Hu, Z., (1996b). The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Diesel Engine Emissions - Part 2: Effects of Carbon Dioxide, SAE Technical Paper 961167, https://doi.org/10.4271/961167 Ladommatos, N., Abdelhalim, S., Zhao, H., and Hu, Z., (1997a). The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Diesel Engine Emissions - Part 3: Effects of Water Vapour, SAE Technical Paper 971659, https://doi.org/10.4271/971659